Steam jet



March 30, 1965 Original Filed Dec. 26, 1962 btates This application is a continuation of my copending application Serial No. 247,099, tiled December 26, 1962, now abandoned and relates to a steam jet, more particularly, a jet whereby steam can be introduced into the pickling solution in a pickling tank for pickling steel articles, such as steel strip, to remove iron oxide from the surface of the steel articles. The jet is useful for introducing steam or any liquid into a corrosive solution, but it is particularly useful for introducing steam into a pickling tank, and, therefore, it will be described with reference thereto.

When steel articles such as bars, strip, plates, etc., are hot rolled, a layer of iron oxide or scale forms on the surface of the articles which must be removed before the steel can be further processed. For example, it is necessary to remove the scale prior to cold reduction of continuous strip, and it is necessary to remove the oxide before the strip can be tin-coated or galvanized. A frequently used method for removing the metal oxide is to dip the steel articles in tanks containing a solution of sulphuric acid.

In order to carry on the chemical reactions involved in pickling as quickly as possible, the sulphuric acid solution is maintained at a relatively high temperature (in the order of 200 to 220 F.) by injecting steam into the solution. Customarily, the steam has been injected into the solution through lead pipes which are resistant to the acid solution. However, since the concentration of the solution is relatively high (in the order of l2 to 25% by weight of acid to total solution), and since the solution is at a relatively high temperature, the lead pipes must be replaced frequently.

The steam jet which I have invented is made of a tetratluoroethylene polymer such as that manufactured by the E. I. du Pont de Nemours and Company under the trademark Teon The resistance of this material to acids is well known. However, another property of Teflon has created difficulties in using this material in steam jets for pickling tanks, and it is the purpose of my invention to solve that difficulty.

Teon steam jets are manufactured by extruding Teiion tubes in the conventional manner. However, since the steam is injected into the tank near the bottom of the tank and since a supply of steam must be piped over the side of the tank, the tubes are bent into a general L-sh-ape having a curved portion and two arms extending at right angles to each other from the curved portion. It has been found that when these tubes are subjected to the high ternperatures maintained in pickling tanks, the tubes, due to plastic memory, tend to straighten out into the straight form which they initially had when they were extruded. The end of the tube within the tank from which steam is ejected rises in the tank, and steam is blown through the surface of the solution in the tank. This is obviously an unsatisfactory situation.

In accordance with my invention, I insert into the Teon tube after it has been extruded a liner in the form of a corrosion resistant metal tube which makes a close fit with the interior of the Teilon tube and extends at least through that portion of the Teflon tube which is to be curved. I then curve the portion of the Teon tube which is lined with the metal tube. The tube prevents the Teflon tube from straightening out due to plastic memory when it is subjected to the temperature of the pickling bath.

In the accompanying drawing I have illustrated a presently preferred embodiment of my invention which comprises a Teflon tube l. which has a curved portion 2 between its ends and two arms 3 and 4 which extend from the curved portion at an angle to each other, preferably an angle of When in use, the arm 3 extends down into the pickling tank, and, accordingly, it has adjacent its end outlet holes 5 through which `steam is ejected into the pickling bath. The outer end of the arm 3 is internally threaded, and a plug 6 is threaded into the end of the arm to close it. The plug is secured in the end of the arm by a transverse pin 7.

In the curved portion 2 of the Teflon tube, and preferably in those portions of the arms 3 and 4 which extend from the curved portion 2, there is a corrosion resistant metal tube 8 which has the same curvature as the Teflon tube. This metal tube may be a stainless steel such as that known as American Iron and Steel Institute type 304 or a steel of the type known under the trademark Monel, which is a high nickel copper corrosion resistant steel alloy.

The outer end of the arm 4- is externally threaded so that the jet can be connected to a source of steam not shown.

The steam jet shown is made by first extruding a tube of Teflon of the desired internal and external diameter and the desired length in the conventional manner. Internal threads are formed in the arm 3 and external threads on the arm 4. A stainless steel tube or liner which has an external diameter making a close t with the internal diameter of the Teflon tube is inserted in the tube through the open end of the arm 4. The Teflon tube with the metal liner is then bent to form the curved p0rtion 2 as shown in the drawing.

While I have described a certain presently preferred embodiment of my invention, it is to be understood that it may be otherwise variously embodied within the scope of the appended claims.

I claim:

l. A jet for introducing steam and liquids into corrosive solutions comprising (A) a hollow tube of a tetrauoroethylene polymer possessing plastic memory,

(l) said tube being curved between its ends to form two arms extending at an angle to each other,

(2) being closed at one end,

(3) having means at the opposite end to connect it to a source of material to be introduced into a solution, and

(4) having outlet holes adjacent the closed end,

and,

(B) a rigid metal liner means resistant to acid corrosion within the curved portion of said tube for preventing straightening of said tube by plastic memory on heating of said tube.

2. A steam jet as described in claim l in which said liner extends into at least a portion of each of said arms.

References Cited by the Examiner UNITED STATES PATENTS 2,027,962 1/ 36 Currie 264-230 2,200,503 5/40 Iudell et al 239-588 2,203,210 6/40 Young Z39-588 2,608,801 9/52 Ridley 239-602 2,631,058 3/53 Ingram et al. 239-591 2,886,853 5/59 Herman et al. 264-230 2,989,785 6/61 Stahl 264-230 EVERETT W. KIRBY, Primary Examiner. 

1. A JET FOR INTRODUCING STEAM AND LIQUIDS INTO CORROSIVE SOLUTIONS COMPRISING (A) A HOLLOW TUBE OF A TETRAFLUOROETHYLENE POLYMER POSSESSING PLASTIC MEMORY, (1) SAID TUBE BEING CURVED BETWEEN ITS ENDS TO FORM TWO ARMS EXTENDING AT AN ANGLE TO EACH OTHER, (2) BEING CLOSED AT ONE END, (3) HAVING MEANS AT THE OPPOSITE END TO CONNECT IT TO A SOURCE OF MATERIAL TO BE INTRODUCED INTO A SOLUTION, AND (4) HAVING OUTLET HOLES ADJACENT THE CLOSED END, AND, (B) A RIGID METAL LINER MEANS RESISTANT TO ACID CORROSION WITHIN THE CURVED PORTION OF SAID TUBE FOR PREVENTING STRAIGHTENING OF SAID TUBE BY PLASTIC MEMORY ON HEATING OF SAID TUBE. 